stix Posted January 16, 2018 Posted January 16, 2018 (edited) Firstly, my apologies if I get some terminology wrong - it's been a while. So my proposal is to build a small shell and use the compositions I've created over the last three years and therefore use them for their intended purpose This is what I have in the way of stars: 1/4" cut stars of various charcoal streamers TT, Spider etc.1/4" cut stars of "Gold Twinkler" - (Glitter) really nice1/4" cut stars of "Silver Comet" - (not sure of category, but very nice)1/4" cut stars of Zinc Granite/Pearl streamers (meh?)1/4" cut stars of Red and Green Nitrate Rubber Starsplus some micro stars/dragons eggs So the only "colours" are the red and green, although the zinc stars do have a certain appeal. Also with most of the above I've got 5/8ths (15mm) pressed comets that were previously and successfully tested in a star gun. The shell/s would be small shells (1 3/4" diam - 45mm) and launched via a mortar. Instead of just throwing a pile of stars together and hoping for the best, I'd like to put them together in a fashion that looks pleasing. The red and green nitrate stars and the zinc stars burn longer than most of the others, so I guess I could cut them smaller? I'm thinking to use the mortar as a star gun with a hole in the bottom side for the fuse to light the lift. I could make a spolette with some 1/4" tubes I have, or I also have some home-made time fuse that could work. There is much work to do. I know my "proposal" is small time, but I would like to do this with an "old school" approach. I can make a former tool, I've got virgin kraft and I'll make the wheat paste and whatever else is required, I'll give it my best shot. Your thoughts on my "proposal" are much appreciated. Cheers. Edited January 16, 2018 by stix 1
MrB Posted January 16, 2018 Posted January 16, 2018 It's harder, since your shell is tiny, but red and green always looks nice together. Layer them along the edge of the shell. I don't like it, but i suspect you would have to boost it, perhaps a lot, to get a reasonable break. If they already are cut n' dry, changing the shape of them is harder. Again, size is working against you, so the rest of them stars would pretty much be the same thing, but just a single type of stars. You could try stacking 2 layers of-set on the ends, rather then the cylinder walls, and slightly under break them for a bow-tie style effect. But it would be somewhat affected by the spolette stealing the space for the center stars on one end. Micro stars n' dragon eggs in small shells like this probably does fine just mixed in with the burst. Boost it so the boom happens quickly, and the effect doesn't burn of inside the shell. Hell. Make 1/4" rapidfire roman candles. Clay plug, BP, paper cap, star, 2 caps, and some milled sawdust added on top for good measure. Repeat to desired length. A strand of black match on opposite sides of the tube inside, all the way down to the clay plug, and a bit of visco on top for delay.I double up with 2 paper caps on top of the stars, since it's sort of sad to hear rapidfire "thrrrup", and see all the stars in the tube go at like 0.5 seconds. And the paper under the star is to get it out of the tube at all, since you got square stars, but tubes tend to be round... Depending on how easy your stars are to ignite you might have to add a tiny amount of BP to the void where the BM is, on the side of the star, just to make sure it does ignite, but tiny is the word, no point in blowing out the sides, or the two caps up top just yet. That is the job for the lift charge. If your composition is just powder at this point, smaller stars might help you a fair bit with the shells you can actually try and make. Still, it's going to be harder to make a charcoal streamer shell, with gold glitter in the center, just due to size. Commercial (consumer grade) firework over here is pretty much all this size, and it's VERY small stars, (2-5mm) that burn slowly, just mixed in with slow flash for burst, in most cases. You are a rocket man. Give your self a slightly easier time, and work with 3" shells? The comets would work as stars for those as well ;- ) 1
pyrokid Posted January 16, 2018 Posted January 16, 2018 I would make some charcoal streamer shells. I recommend against drilling fuse holes in your mortars. Lifting and leadering are critical elements of shell building. Importantly, these small shells don't consume large amounts of materials, so you can make quite a few in order to refine your technique. 1
Wiley Posted January 16, 2018 Posted January 16, 2018 These are small shells, but that doesn't make it "hard" to get nice results, nor does it mean that you can't have more than one type of color in there. When I was making these, I used little flash bags filled with 2:1:1 kno3:sulfur:Indian blackhead aluminum. Single breaks got 4g, and multibreaks used 2g. The space around the flash bag was filled with 1/4" or a hair smaller stars packed in -8+12 mesh polverone. That was just real polverone: just screen mixed 75:15:10 with +5% dex wetted and screen granulated. I spiked them with 2 strands of well-pasted size 3 crochet thread running together, and pasted them in with some crappy ~70lb paper. Some examples: https://m.youtube.com/watch?v=TIiKnxnX6FI Glitter and charcoal comps (usually tiger Willow) were always cut to 1/4" and never primed. https://m.youtube.com/watch?v=8jEKVdmbCZA https://m.youtube.com/watch?v=NbFZ9gP4qTw https://m.youtube.com/watch?v=xIRTIqaK3Sk https://m.youtube.com/watch?v=_uYYOjbvcPc 2
stix Posted January 20, 2018 Author Posted January 20, 2018 (edited) Thanks for all the ideas, much appreciated. It seems it's always going to be difficult to break such a small shell without the use of flash - which I don't have and it's also something I don't want to be making. Maybe I should just do a couple of roman candles as suggested, or make a larger shell and put atop a sugar rocket. I did look at the sugar rocket idea a while back and the main issue was going to be how to pass fire to the shell. Also it would be good to have a nice tail because sugar rockets do look very boring. I've got some Ferrotitanium (I think). It was meant to be pure Ti but never looked white in the comp and then I discovered it was magnetic!! Edited January 20, 2018 by stix
MrB Posted January 20, 2018 Posted January 20, 2018 I did look at the sugar rocket idea a while back and the main issue was going to be how to pass fire to the shell. Passing fire to the shell could pretty much be the same thing regardless of if you lift them with rockets, or mortar. You just need a shorter delay on the rocket lifted one. And / or, less delay built in to the rocket it self. Hell, build it so the spolette touches the top of the motor, that should pretty much make certain it lights of. Also it would be good to have a nice tail because sugar rockets do look very boring. I've got some Ferrotitanium (I think). It was meant to be pure Ti but never looked white in the comp and then I discovered it was magnetic!! You probably already know, but with any Ti, don't use tooling you like. It sort of eats it alive. You could make cored motors, and have a layer above the core with Ti, and then just a very fast / short spolette / time fuse, to pass the fire in to the shell, if you want to add looks to it. 1
stix Posted January 20, 2018 Author Posted January 20, 2018 (edited) Thanks B, it's all coming back to me now. Lot's of difficulties - but doable. The intention was to use a cored motor as I don't think a sugar motor end burner (even if doped with RIO) would provide enough thrust. I'm not sure how I would secure a layer above the core and ensure there was not blow-through that ignited the shell early (ie. at take-off) The motor tube casing I would be using is 3/4" (19.3mm) ID. The small cardboard tubes I was thinking of using for a spolette are approx. 9mm OD which doesn't leave much room to secure as an end plug. I remember someone did mention an alternate method of using quickmatch applied externally which was lit at the same time as the motor ignited, which in turn ignited the spolette/time fuse for the shell.--So mixing FeTi directly with the sugar propellant is not a good idea - I guess perhaps the Fe would become oxidized or corroded over time? Edited January 20, 2018 by stix
MrB Posted January 20, 2018 Posted January 20, 2018 The intention was to use a cored motor as I don't think a sugar motor end burner (even if doped with RIO) would provide enough thrust. I'm not sure how I would secure a layer above the core and ensure there was not blow-through that ignited the shell early (ie. at take-off) Dunno. Depends on how you make the rocket, i suppose. Casting the rocket would make it easy, just ram or cast the delay (pretty much the same as your rocket fuel with added FeTi, i suppose) on top of it. If you fell it isn't strong enough on it's own, ad a clay cap on top, and drill it back. Avoiding it would be easier, but, what ever it takes. The motor tube casing I would be using is 3/4" (19.3mm) ID. The small cardboard tubes I was thinking of using for a spolette are approx. 9mm OD which doesn't leave much room to secure as an end plug. I remember someone did mention an alternate method of using quickmatch applied externally which was lit at the same time as the motor ignited, which in turn ignited the spolette/time fuse for the shell. I THINK i would just make sure the engine throws a lot of fire in the top once it is spent, and just put the spolette in harms way, so to speak. If you put a clay bulkhead on top of the "delay" you might want to ram a bit of dry mix KNO3/sugar in top, and drill it back out just so you know you are passing fire through the plug in a good way. I'm not exactly sure how much "fire" would be pushed through the clay plug, and the passthough hole drilled in it, and it would be a shame to have a rocket fall out of the sky, never lighting the shell. I don't use KNO3 / sugar, so i have no experience, with BP all i do is ram the delay on top, and then just don't cap it with anything. Stick the timefuse / spolette in to the void, and paste the shell to the rocket, and i'm done. So mixing FeTi directly with the sugar propellant is not a good idea - I guess perhaps the Fe would become oxidized or corroded over time? I would honestly have no idea. But i doubt anything with a 30% or higher titanium content, oxidizes much. You could probably mix it with the fuel, but it would mean you have to consider your tooling expendable. If you are casting the engine, as a solid slug, and want to drill it out, you aren't going to drill the FeTi, it will just cut groves in your core wall, on it's way out. If you cast it around a core, it might bite in to it and be difficult during extraction, and if you try to ram it, the FeTi tends to eat the tooling to bits, getting well stuck on the core, and wearing away on the edges of the rammer. As i said, no idea how you plan to go about the construction of the rocket. If you can cast the engine in the tube, around a core, and then just extract the core, i THINK that would be the most repeatable / consistent method, but extracting a core plug from a sticky fuel grain... not so sure about that.
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